Effect of error-correcting code using DS-3 framing bits on measured dribble-error pattern of 565 Mbit/s fibre optic transmission system

22 days of error-second data were obtained from a DS-3 tributary of a 565 Mbit/s FOTS to predict the effect of a rate 0.99118 FEC code embedded in the DS-3 masterframe overhead. Using DS-3 masterframe parity to resolve errors within multiply-errored seconds, the code corrects all of the 1189 errors observed. There was no evidence for burstiness at the bit-by-bit timescale.